The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Generally, when power is first applied to a system, it takes a time period for a crystal oscillator to build up a magnitude of an oscillation signal to a relatively stable level. Based on the stabled oscillation signal, a system clock is generated. Then, the system clock is distributed in the system, and used by various circuits in the system.